[tex] \frac{ - 5a \times 3b \times 4 { {ab}^{2}} }{10} = \frac{ - 15ab \times 4 {ab}^{2} }{10} = \frac{ - 3ab \times 4 {ab}^{2} }{2} = \frac{ - 3ab \times 2 {ab}^{2} }{1} = - 6 {a}^{2} {b}^{3} [/tex]
